fs: nvs: Add recovery path for corrupted NVS

When all sectors of the settings partition have some data that is not 0xFF, NVS will fail to initialize settings. Add a recovery path to erase the whole settings partition and recover. Should not happen unless there's some serious flash corruption, or possibly interrupted garbage collection. Verified by recreating the scenario with flash CLIs.

Signed-off-by: Cory Andrew Mayer <[email protected]>

subsys/fs/nvs/Kconfig

@@ -37,6 +37,14 @@ config NVS_DATA_CRC
 	  The CRC-32 is transparently stored at the end of the data field,
 	  in the NVS data section, so 4 more bytes are needed per NVS element.
 
+config NVS_INIT_BAD_REGION
+	bool "Non-volatile Storage bad partition recovery"
+	help
+	  Enable automatic initialization of a NVS on a flash region that does
+	  not contain a valid NVS. A region containing an invalid NVS can be
+	  caused by corruption or by providing a non-empty region. This option
+	  ensures a new NVS can be created.
+
 module = NVS
 module-str = nvs
 source "subsys/logging/Kconfig.template.log_config"

subsys/fs/nvs/nvs.c

@@ -781,10 +781,23 @@ static int nvs_startup(struct nvs_fs *fs)
 			}
 		}
 	}
-	/* all sectors are closed, this is not a nvs fs */
+	/* all sectors are closed, this is not a nvs fs or irreparably corrupted */
 	if (closed_sectors == fs->sector_count) {
+#ifdef CONFIG_NVS_INIT_BAD_REGION
+		LOG_WRN("All sectors closed, erasing all sectors...");
+		rc = flash_flatten(fs->flash_device, fs->offset,
+						   fs->sector_size * fs->sector_count);
+		if (rc) {
+			goto end;
+		}
+
+		i = fs->sector_count;
+		addr = ((fs->sector_count - 1) << ADDR_SECT_SHIFT) +
+			   (uint16_t)(fs->sector_size - ate_size);
+#else
 		rc = -EDEADLK;
 		goto end;
+#endif
 	}
 
 	if (i == fs->sector_count) {